Pay.
That one's a no-brainer. Using the points on this cheap stay takes you out of the Travel Package levels, which is where the most bang-for-buck for MR points is had. Now that you've found us

, search the board for all sorts of discussions about Travel Packages, plus all sorts of info about where people commonly use their Marriott points.
Enjoy the JW, especially at that rate!! Welcome to FT!!
Also, if the $149/nt is a publicly-available rate, and you wish to bring it down somewhat, acquire a couple of Premium Pounds or Bonus Bucks certificates. Do a search here for more information about these certificates if you aren't familiar with them.